From practice, tube clamps with a mechanical effect for medical tubes such as infusion lines, blood circuits, but also for tubes used in laboratories arc known. Such tube clamps fit tightly on the exterior of the tube. They may be manually taken into an open position in which they do not hinder the fluid flow in the tube, or into a closed position in which they reduce or stop the fluid flow, e.g., by squeezing or clamping the tube. Therefore, tube clamps serve as mechanical control systems for the flow of medical fluids through the tube, e.g., of blood, infusion solutions such as isotonic solutions, and medication.